The key problem with the GMG GM sections is that it comes off as written by people only very superficially knowledgeable of Pathfinder 2.This seems to be the key problem. Pathfinder 2e does not sufficiently communicate in your opinion that the GM is empowered to make rulings. It’s implied in the Core Rulebook, but the Gamemastery Guide makes it explicit. It goes on to list a few examples, including things that could possibly be feats someday (such as swinging from a chandelier or throwing sand in an opponent’s eyes), but it says it’s okay to let players try them.
The advice on how to create and group encounters, for instance, the bit about the heroes infiltrating a castle, is a recipe for disaster in PF2. (combining even two moderate encounters can easily lead to a TPK - a very significant difference between the two editions) I can't prove it of course, but to me it feels lifted straight out of (appropriate) advice for PF1.
So excuse me if I don't have a high confidence level for the passage you quote. It comes across as wishful thinking, expressive of what a game they wished they'd designed rather than the game they actually designed.
In short: the actual design defeats the goal of empowering the GM.
As I have stated: PF2 is not, I repeat not, a game that trusts its GM. Paizo writes rules for every single little thing. That is the obvious indicator of a game that is not willing to leave decisions in the GMs hands.
Again: just because Paizo says their game does this or that does not make it so. Yes, they claim they have created such a game, but when you look at how the game actually works, I'm pointing out that there is nothing there to indicate they have met that goal. (That's my criticism!)
If by sheer luck those chandeliers-swinging examples haven't been invalidated yet by feats (Swashbuckler feats perhaps?) they will soon be. But this misses the bigger point: how are a GM to know when and where he or she can be generous and issue rulings? By learning dozens and dozens of feats by heart, is the answer and it is unreasonable and needs to be called out as such!
Tl;dr: please don't meet my criticism by pointing toward generic aspirations. I am pointing to actual rules and actual rule interactions. I hope you agree a game designer can't just fix flaws in their design by hopeful words!